Nowadays, the air pollution problems are becoming increasingly serious in our country and its neighboring regions. In particular, the concentration of fine suspended particles (e.g. Particulate Matter 2.5, PM 2.5) is often too high. Hence, the monitoring of the concentration of suspended particles in the air is getting attention. However, since the air flowing with the wind direction and the air volume is not quantitative and the air quality monitoring stations for detecting suspended particles are mostly fixed points, it is impossible to confirm the concentration of suspended particles in the current surroundings. Hence, a miniature portable gas detecting device is needed. It allows users to measure the concentration of suspended particles around the surrounding, anytime and anywhere.
Moreover, the conventional gas detecting devices are often only capable of detecting a single substance (e.g., suspended particles) in the air. However, in addition to the suspended particles described above, there are many gases harmful to the human body in daily life. It would influence the health of the human body if we don't detect the harmful gases and suspended particles simultaneously.